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Porous materials displaying tailor-made pore sizes and shapes are particularly interesting in a great variety of real and potential applications where molecular recognition is needed, such as shape-selective catalysis, molecular sieving, and selective adsorption.[1±4] Classically, apart from silica, materials most commonly used for catalysis and catalyst supports have been those based on high surface aluminas, owing to their thermal, chemical, and mechanical stability and their low cost.[5] Earlier aluminas with high surface areas (~500 m 2 /g) had been prepared using structure-directing agents. However, they were X-ray amorphous materials and their porosity was purely textural, characterized by wide pore size distributions.[5] More recently, the discovery by researchers at Mobil of the M41S family of mesoporous silicas synthesized by using micellar aggregates as templates, [6,7] has promoted considerable development in the synthesis of materials with uniform pores in the mesoporous range.[8±14] However, in the case of mesoporous aluminum oxide, the usual strategies used in the synthesis of mesoporous silica have not always yielded satisfactory results and only a few papers have reported on surfactant-assisted synthesis of mesoporous alumina. Davis and co-workers [15] have reported the preparation of aluminas with narrow pore size distributions by the use of anionic surfactants but their solids always have an approximately constant pore size (ca. 20 ) that cannot be tailored by changing the surfactant length. Conversely, Pinnavaia and co-workers [16,17] report the use of neutral polyethylene oxides as directing agents for the synthesis of mesoporous solids for which both the d spacing and the pore diameters increase as the surfactant size does. In both cases, the synthetic pathway is based on typical procedures originally used for mesoporous silicas: the variation of the micelle diameter is achieved by increasing the surfactant chain length and/or addition of hydrophobic organic molecules. However, the scarcity and diversity of the reported results suggest that there is still a long way to go to obtain real control of the synthetic procedures for the preparation of mesoporous aluminas.In this context, we show that self-assembling processes leading to the formation of mesoporous aluminas can be controlled by adequately balancing such processes and the hydrolysis and condensation reactions occurring at the inorganic phase. This method has allowed us to isolate for the first time mesoporous aluminum oxides using cationic surfactants and, what is more important, to tune their pore size by the sole adjustment of the molar ratio of the reactants.Thermally stable aluminas with different pore diameters, henceforth denoted as ICMUV-1, were synthesized using CTABr (cetyltrimethylammonium bromide) as surfactantdirecting agent in a water/TEA (triethanolamine) medium. A constant 2/1 Al/CTABr molar ratio was always used, and the pore size adjustment was achieved by changing the Al (or surfactant)/water/TEA molar ratio.A typica...

Pure mesoporous aluminum phosphonates and diphosphonates have been synthesized through an S + Isurfactant-assisted cooperative mechanism by means of a one-pot preparative procedure from aqueous solution and starting from aluminum atrane complexes and phosphonic and/or diphosphonic acids. A soft chemical extraction procedure allows opening the pore system of the parent mesostructured materials by exchanging the surfactant without mesostructure collapse. The hybrid nature of the pore wall can be modulated continuously from organic-free mesoporous aluminum phosphates (ALPOs) up to total incorporation of organophosphorus entities (mesoporous phosphonates and diphosphonates). The organic functional groups become basically attached to the pore surface or inserted into the ALPO framework (homogeneously distributed along the surface and inner pore walls) depending on the use of phosphonic or diphosphonic acids, respectively. X-ray powder diffraction, transmission electron microscopy, and surface analysis techniques show that these new hybrid materials present regular unimodal pore systems whose order decreases as the organophosphorus moiety content increases. NMR spectroscopic results not only confirm the incorporation of organophosphorus entities into the framework of these materials but also provide us useful information to elucidate the mechanism through which they are formed.

Use of functionalized MCM‐41 solids as anion sensing systems has been demonstrated for the first time. The combination of the binding properties of molecular receptors with the structural characteristics of solid, inorganic surfaces leads to remarkably enhanced anion sensing response. The Figure shows a schematic view of a solid surface, with 300 Å diameter holes that are filled with aminoanthracene molecules.

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